That switch controls a "Big Boy" relay (
https://www.google.com/url?sa=t&sour..._4C3EsKtdmamDQ) located just forward of the wet bay behind a carpeted panel held on by Velcro. Perhaps it is showing signs of failure.
In 2017 Entegra switched to a Blue Sea relay (
http://www.bluesea.com/products/7700..._-_12V_DC_500A).
If it fails not to worry, you can move the big cable from one side of the relay to the other (connecting the two big cables together) to bypass it until you can receive a replacement.
The Blue Sea relay is probably a lot more reliable if you have a choice of replacement device.